This invention relates generally to gas turbine engine turbines and more particularly to structural members of such engines.
Gas turbine engines frequently include a stationary turbine frame (also referred to as an inter-turbine frame or turbine center frame) which provides a structural load path from bearings which support the rotating shafts of the engine to an outer casing, which forms a backbone structure of the engine. Turbine frames commonly include an annular, centrally-located hub surrounded by an annular outer ring, which are interconnected by a plurality of radially-extending struts, as well as one or more service tubes which carry fluids to and from the hub. The turbine frame crosses the combustion gas flowpath of the turbine and is thus exposed to high temperatures in operation.
From a thermodynamic standpoint it is desirable to increase operating temperatures within gas turbine engines as much as possible to increase both output and efficiency. However, as engine operating temperatures are increased, increased active cooling for turbine frame, turbine nozzle, and turbine blade components becomes necessary.
Conventional service tubes are mounted internal to the struts of the frame and are inseparable from the frame. High temperature operation tends to cause undesirable oil coking within the service tubes.